Portable electric hammer



Aug. 8, 1933.

Filed June 6, 1932 R. H. MAXWELL ET AL PORTABLE ELECTRIC HAMMER 2 Sheets-Sheet l Aug. 8, 1933.

R. H. MAXWELL |=:r AL

PORTABLE ELECTRIC HAMMER Filed Junel 6, 1932 2 Sheets-Sheet 2 o., m1@ y QW @Mud n .c fwn f@ if FB Patented ug. 8, 1933- PATENT oFFIcE PORTABLE ELECTRIC HAMIMER Wilmette. Ill.

Ralph H. Maxwell and Frederick J. W'eidling,

Application June 6, 1932. Serial No. 615,678

9 Claims.

Our invention relates to improvements in portable electric hammers, and it consists in the combinations, constructions, and arrangements herein described and claimed.

An object of our invention is to provide a.

portable electric hammer in which vibration is reduced to a' minimum, and which may be operated for a long period of time without tiring the operator.

tric hammer having novel means for rotatinga tool associated therewith when the device isv in operation.

A further object is to provide a portable electric hammer which in turn is provided with novel means for having a tool connected therewith.

A further object is to provide a portable electric hammer having novel means for lubricating certain parts thereof.

A further object is to provide a portable electric'hammer which is simple and sturdy in construction, and which may be readily assembled and disassembled for being serviced.

Other-objects and advantages will appear in the following speciiication, `and the novel features of the invention will be particularly pointed out in the appended claims.

Our invention is illustrated in the accompanying drawings, forming part of this application, in which Figure 1- is a longitudinal sectional view of the device,

Figure 2 is a view taken substantially along the line 2 2 of Figure 1, certain portions thereof being shown in elevation,

Figure 3 is a detail view of a portion of the device,

Figure 4 is a detail sectional view taken along the line 4-4 of Figure 1,

Figure 5 is a detail sectional'view taken along the line 5-5 of Figure 1,

Figure 6 is a detail sectional view taken along the .line 6-6 of Figure l, and' Figure 7 is a detail sectional View taken along the line 7-7 of Figure 1.

lto theV gear.

In carrying out our invention, we provide a housing 1 having a chamber 2 therein and provided With threaded end portions 3 and 4. The housing 1 comprises in part an outwardly projecting portion 5 having a cylindrical opening 6 60 therein for receiving a bearing member 7. A gear 8 is rotatably mounted in the chamber 2 and is provided with a shaft portion 9 which is rotatably positioned in the bearing member '7. The gear 8 is further provided with an eccen- 65 trically positioned cam portion l0.

The shaft portion 9 and the cam portion 10 may be integral with the gear 8 or fixedly connected therewith in any suitable manner. An annular plate member 11 is positioned on the 70 shaftA portion 9 between the cam portion 10 and the housing for properly positioning the gear 8 and the cam portion 10.

A connecting pin 12 is iixedly connected with the gear v8 and is eccentrically positioned with 75 respect thereto. A connecting rod 13 has one endv 14 pivotally mounted on the connecting pin 12 and is retained thereon by any suitable` means, such as a cotter pin 15. The connecting pin 12 may be provided with an annular flange 80 portion or a ring member 16 positioned between the connecting rod 13 and the gear 8 for properly positioning the connecting rod with respect The end 17 of the connecting rod extends Within la recess 18 oi a piston member 85 19 and is pivotally connected with the piston member 19 by any suitable means, such as a connecting pin 20. The piston member 19 is slidably disposed in a cylindrical chamber n21 w oi' a reciprocable hammer member 22. 90

The hammer member 22 is provided with an annular recess in the cylinder wall adjacent an end thereof for receiving a retaining 'ring 23. The retaining ring is for the purpose of preventingthe piston 19 from being accidentally moved 95 out of the cylinder chamber 21. The hammer member 22 isl slidably disposed in a sleeve member 24 and is provided with reduced portions 25 which in turn provide spaces 26 between the -hammer member and the sleeve 24, which aid in reducing the friction between the hammer member and the sleeve.

f The hammer member 22 is provided with a solid reduced end portion. 27.V The sleeve 24 has an end portion thereof positioned within the housing 1 and terminating in a circular row of teeth 28. The sleeve 24 is provided with a circumferential ange portion 29 for engagement with the housing l for positioning the sleeve 24 With respect to the housing.

The housing 1 is provided with an internal flange ,portion 30. A resilient means is positioned between the hammer member 22 and the flange portion 30, and comprises a retaining band 31 which is anglular in cross section and in engagement with the ange portion 30.

A cushioning band 32 is positioned in engagement with the band 31 and between the band 31 and an auxiliary band 33. The cushioning band 32 may be of any shock-absorbing material, such as rubber.

A tubular casing 34 is disposed over the sleeve 24 and is provided with an internallythreaded end portion for being connected with the end portion 4 of the housing 1. rIhe easing 3491s provided with an internal and circumferential flange portion 35 disposed in spaced-apart'relationship with respect to the flange portion 29 of the sleeve 24.

A helical spring 36 is positioned between the iiange portionsf29 and 35 and is for the purpose of yieldingly retaining the sleeve 24 in a given position, at which time the flange 29 is in engagement with the housing 1.

It wll be noted at this time that the piston 19, the hammer member 22, and the sleeve 24 are provided with openings 37, 38, vand 39, respectively, the purpose of which will behereinafter set forth.

As shown in Figures' 1 and 3, a reciprocatory and oscillatory pawl member 40 is positioned between the gear 8 and the plate member 11 and is provided with an elongated opening 41 therein for receiving the'cam portion 10. The pawl member 40 isalso provided with an elongated opening 42 therein for receiving a pin 43 which may be threaded for being connected with the housing 1 and locked in engagement therewith by a nut 44. The pawl member 40 is provided with teeth 45 in engagement with the teeth 28 of the sleevemember 24 for rotating the sleeve member when the pawl memberis oscillated. The pawl member 40 may also be provided with an arcuate-shaped end 46.

The housing 1 may be provided with a bracket portion 47 which may be connected with the housing by any suitable means, such as la set screw 48. The bracket member is provided with a projecting portion 49 which is positioned in spaced-apart relation with respect to the end 46 of the pawl 40 and is provided with an opening 50 therein for receiving a spring 51 which bears against a spring-pressed member 52 in engagement with the arcuate-shaped end portion 46 of the pawl 40 for yieldingly retaining the -teeth 45 of the pawl member in engagement with lthe teeth 28 of the sleeve 24. Thus it will be seen that when the cam portion 10 is rotated that the pawl member 40 will be oscillated for rotating the sleeve 24.

' The sleeve 24 is provided with an end portion 53 which extends therewithin and may be connected in any suitable manner, such as by sweating or welding. The end member 53 is provfded with a cylindrical recess 54 therein which is substantially concentric with the sleeve 24. A plate member 55 is movably disposed within the recess 54 and may be retained therein by .any suitable means, such as a split ring 56 in engagement with the end member 53.

The end member 53 is further provided with a passageway 57 therein which is substantially concentric therewith. A portion 58 of the passageway 57 may be hexagonal in cross section, while a portion 59 of the same passageway may be circular in cross section for receiving the stem 60 of a tool having corresponding hexagonal and circular portions so that the tool may be rotatedwhen the sleeve 24 is rotated.

A cap member 61 may be connected with the end member 53 by any suitable means, such as having a threaded portion 62 thereof connected with a threaded portion 63 of the end member 53. A split collar 64 is disposed within the cap member 61 and comprises a pair of collar portions 65 and 66. The split collar 64 has a portion 67 thereof disposed in spaced-apart relationship with respect to the stem 60 of the tool and another portion 68 thereof of reduced diameter and adapted for` engagement with the tool.

A resilient band 69 of any suitable material, such as rubber, encircles the reduced portion 68 of the split col1ar,64 for holding the collar in engagement with the stem of the tool. The stem 60 of the tool may be provided with a pin 70 extending therethrough and projecting beyond diametrically-opposed sides thereof for engaging the reduced portion of the split collar 64 whereby the stem of the tool may be retained within the collar. The stem 60 may be pro- ,vided with projecting portions or lugs in lieu "-of the pin 70, if so desired.

The cap member 61 is provided with a constricted end portion 71 for retaining the split collar 64 and the resilient band 69 therewithin. The housingn 1 is provided withv an opening 72 therein for receiving a cover member 73. The cover member 73 may be connected with the housing by any suitable means, suchV as screws, not shown.

A pad 74 of absorbent material is disposed within the cover member 73 and may be connected therewith in any suitable manner. The absorbent pad 74 is provided with an internally projecting portion 75 which is positioned for engaging the connecting pin 12 during each revoluton of the gear 8. The absorbent pad 74 may be saturated with oil which will be transmitted through the projecting portion 75 of the pad to the connecting pin 12 for lubricating the bearing surfaces between the connecting pin and the connecting rod. l i

A motor housing `76 has one end connected with the threaded end portion 3Y of the housing 1 and is provided with an end portion 7,7 which may be iixedly connected therewith in any suittioned between the housing 1 and the motor housing 76 and fixedly held in position by means of an internal ange portion 85 integral with the motor housing 76. The retaining member is provided with an opening 86 through which the shaft '87 of the armature extends.

A gear 88 is mounted on the shaft 87 and is inv mesh with the gear 8 so that the gear 8 may be rotated when the motor is in operation. The motor housing 76 and the end portion 77 are provided with openings 89 therein for receiving brushes 90, which, of course, comprise .a part of the motor and are associated therewith in the conventional manner. The end portion 77 of the housing 76 is provided with a projecting portion 91 which in turn is provided with a reduced portion 92 for forming a shoulder portion 93.

A cover member 94 is provided with a central opening 95 thereinthrough which the reduced portion 92 extends and engages the shoulder portion 93 for being properly positioned with respectI to the projecting portion 91. A ring 96 extends over the end of the projecting portion 91 and has a pin 97 extending therethrough and also through the projecting portion 91 for connecting the cover member 94 with the projecting portion 91.

The cover member 94 is provided with a hollow handle portion 98 which contains a switch mechanism 99.v .A switch actuating member 100 is operatively associated with the switch mechanism and extends through an opening in the handle portion so that the same may be manually actuated by an operator. An insulating plate 101 is iixedly connected with the cover member 94 by any suitable means, such as screws 102, and in like manner, an insulating plate 103 is connected with the end portion 77 of the motor housing 76.

Contact elements, 104 and 105 are connected with the insulating plate 101 and are in engagement with contact rings 106 and 107, respectively, which are mounted in the insulating plate 103, and which are disposed in concentric and spacedapart relationship.

The end portion 77 is provided with openings 108 through which conductors 109 may extend for providing electrical communication between the contact rings and the magnetic field of the motor. 'Ihe contact elements 104 and 105, together with the switch mechanism 99, are .in communication with a source of current by means of conductors 110.

The motor housing 76 and the cover member 94 are provided with openings 111 and 112 therein so that air may circulate through the motor housing 7d for cooling the motor.

cess 114 and positioned on opposite sides 'of the.

pawl member for retaining the bands in position. The lug portions 115 are disposed in spacedapart positions with respect to the pawl member so as not to hinder the movement thereof.

From the foregoing description of the various parts of the device, the operation thereof may be readily understood. When it is desired to put the device in operation, the operator actuates the switch actuating member 100 for closing the circuit, thereby causing the motor to operate for reciprocating the piston 19 through the gears 88, 8, and the connecting arm 13.

In following through the operation of the device, Vit will be seen that as the piston 19 moves downwardly, it will compress, the air lin the chamber 116 between the piston and the hammer member, which will result in driving the hammer member downwardly for striking the plate member 55.' This impingement of the hammer member on the plate member is .transmitted 'to the stem 60 of the tool, therebyr causing the tool to move into the material with which it is in contact.

A fan 113 is' mounted on the armature shaft 87 for circulatingI 4It vwill be noted, however, that when the plate 55 engages the shoulder portion 117 of the end portion 53 that the shock thereof is absorbed by the spring 36 which tends to yieldingly resist the movement of the sleeve 24 downwardly.

When the piston 19 and the hammer member` 22 have reached their extreme downward positions, the air in the chamber will be compressed momentarily but may escape throughthe minute openings 37, 38, and 39.

As the piston is moved upwardly, it will create a suction within the chamber 116, thereby causing the hammer member 22 to 'also move upwardly. As the hammer member approaches its extreme uppermost position, its speed will be lessened by reason of the air rushing through the openings 38 and 39 for overcoming the suc- Ition in the chamber 116. :When the hammer y Thus it will be seen that when the device is in operation, not only will the hammer member be reciprocated at a great rate of speed, but also that the tool will be rotated a portion of a revolution at each reciprocation of the hammei` member.

If it is desired to dispense with the rotating feature of the device, it is merely necessary to remove the pawl member 40. 'Ihe pawl member i and the cam portion 10 are of course so related that the sleeve member 24 will be moved through a portion of a revolution when the hammer member is moved through its up stroke.

It will be noted that the tool is so associated with the device that it cannot be driven 'out of engagement therewith when the device is operated without the tool being in engagement with material to be worked. This construction eliminates the danger of the tool being driven from the device when the switch member is accidentally operated for energizing the motor. Ihe

- construction is such, however, that the tool may be readily removed orreplaced by another.

The outwardly] projecting portion 5 of the housing 1 may be provided with a pair of spacedapart flange portions 118. A handle member 119 provided with an elliptical-shaped portion 120 positioned between the flange portions 118 and pivotally connected therewith by means of a pin 121 extending through the elliptical portion 120 and the flange portions 118. The handle 119 may be moved to the dotted line position 122, at which time the 'elliptical portion 120 will engage the portion 5 of thehousing for retaining the handle in its transverse dotted line position.

The advantages of this feature are that the device may be more easily controlled when in operation, and additional pressure may be exerted on the device for holding the tool in erigagement with the work. V

The projecting portion 5 may be provided with an opening therein for receiving a plug or screw member 123 so that the bearing 7 containing the shaft 9 may be lubricated.

We claim:

1. A portable power hammer lcomprising a housing, a motor mounted in the housing, a reciprocable sleeve operatively connected with the housing, a reciprocable hammer slidably disposed in the sleeve, a reciprocable piston slidably disposed in the hammerand operatively associated therewith for reciprocating the hammer when the piston is reciprocated, means operatively connecting the piston with the motor for reciprocating the piston when the motor is operated, and means connected with the sleeve for receiving a tool.

2. A portable power hammer comprising a housing, a motor mounted in the housing, a reciprocable sleeve operatively connected with the housing, a reciprocable hammer slidably disposed in the sleeve, a reciprocable piston slidably disposed in the hammer and operatively associated therewith for reciprocating the hammer When the piston is reciprocated, means operatively connecting the piston with the motor for reciprocating the piston when the motor is operated, means connected with the sleeve for receiving a tool, and cushioning means for yieldingly retaining the sleeve against longitudinal movement.

3. A portable power hammer comprising a housing, a motor mounted in the housing, a reciprocable sleeve operatively connected with the housing, a reciprocable hammer slidably disposed in the sleeve, a reciprocable piston slidably disposed in the hammer and operatively associated therewith for reciprocating the hammer when the piston is reciprocated, means operatively connecting the piston with the .motor for reciprocating the piston when the motor is operated, means connected with the sleeve for receiving a tool, and means operatively associated with th'v sleeve for rotating said sleeve when the piston is reciprocated. y

4. A portable power hammer comprising a housing, a motor carried by the housing, a sleeve operatively associated with the housing and movable with respect thereto, a reciproc'able hammer slidably disposed in the sleeve, a reciprocable piston slidably disposed in the hammer and operatively associated therewith for reciprocating the hammer whenthe piston is reciprocated, means operatively associating the 5. A portable power hammer comprising a.

housing, a motor carried by the housing, a sleeve operatively associated with the housing and movable with respect thereto, a reciprocable hammer slidably disposed in the sleeve, a reciprocable piston slidably disposed in the hammer and operatively associated-therewith for reciprocating the hammer when the piston is reciprocated, means operatively associating the piston with the motor for reciprocating the. piston when the motor is operated, means connected with the sleeve for receiving a tool, and a movable element associated with the tool-receiving means and adapted for engaging with a tool associated therewith, said movable element being positioned between the tool and the hammerfor receiving the impingements of the hammer when the same is reciprocated.

6. A portable power hammer comprising a gear housing, a motor housing connected with the gear housing, a motor mounted in the motor housing, a handle means connected with the motor housing and provided with a switch for controlling the operation ofsaid motor, a driving gear connected with the motor and in mesh with a driven gear rotatably mounted in the housing, a sleeve operatively associated with the housing and movable with respect thereto, a reciprocable hammer slidably disposed in the sleeve, a piston slidably disposed in the hammer and operatively associated therewith, a connecting rod operatively connected with the driven gear and the piston for reciprocating the ham- 'mer when the motor is operated, said sleeve being provided with a toothed end portion, and a pawl member operatively associated with the driven gear and the toothed -end portion for rotating the sleeve intermittently when the piston is reciprocated. y

7. A portable power hammer comprising a gear housing, a. motor housing connected with the gear housing, a motor mounted in the motor housing, a handle means connected withl the motor housing and provided with a switch for controlling the operation of said motor, a driving gear connected with the motor and in mesh with a driven gear rotatably mounted in the housing, a vsleeve operatively associated with the housing and movable with respect thereto, a.

reciprocable hammer slidably disposed in thesleeve, a piston slidably disposed in the hammer and operatively associated therewith, -a connecting rod operatively connected with the driven gear and the piston for reciprocating the hammer when the motor is operated, a casing portion connected with the gear housing and positioned exteriorly with respect to the sleeve, said sleeve and casing portion being provided with spaced-apart ilange portions, resilient means positioned between the ilange portions for yieldingly retaining the sleeve in a given position, said sleeve being provided with a toothed end portion, and a pawl member operatively associated with the driven gear and the toothed end portion for rotating the sleeve intermittently when the piston is reciprocated.

8. A portable power hammer comprising a gear housing, a motor housing connected with the gear housing, a motor mounted in the motor housing, a handle means connected with the motor housing and provided with a switch for controlling the operation of said motor, a driving gear connected with the motor and in mesh with a driven gear rotatably mounted in the housing, a sleeve operatively associated with the housing and movable with respect thereto, a reciprocable hammer slidably disposed in the sleeve, a piston slidably disposed in the hammer and operatively associated therewith, a connecting rod operatively connected with the driven gear and the piston for reciprocating the hammer when the motor is operated, saidsleeve being provided with a toothed end portion, a cam portion associated with the driven gear, and a pawl memberassociated with the cam portion and in engagement with the toothed portion 'of the sleeve, said pawl member being operable by the cam portion for rotating the sleeve when the drivengear is rotated.

9. A portable power hammer comprising a gear housing, a motor housing connected with the gear'housing, a motor mounted in the motor housing, a handle means connected with thel motor housing and provided with a switch for controlling the operation of said motor, a driving gear Aconnected with the motor and in mesh with a driven gear rotatably mounted in the housing, a sleeve operatively associated with the housing and movable with respect thereto, a reciprocable hammer slidably disposed in the sleeve, a piston slidably disposed in the hammer and operatively associated therewith, a connecting rod operatively connected with the-driven gear and the piston for reciprocating the hammer when the motor is operated, a casing portion connected with the gear housing and positioned exteriorly with respect to the sleeve, said sleeve and casing portion being provided with spaced- 

